One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(15,21)(16,24)(18,26)(20,27)(22,28)(23,25) involution — undirected(1,2,4,3)(5,6)(7,10)(8,9)(11,12)(13,14)(15,22)(16,20)(17,19)(18,23)(21,28)(24,27)(25,26)(1,3,4,2)(6,9)(7,11)(13,15,17,23)(14,18,19,22)(16,25,24,21)(20,28,27,26)(5,7,8,11)(6,10,9,12)(14,19)(15,23)(20,27)(21,25)(6,9)(10,12)(14,19)(18,22)(20,27)(26,28) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.